Drilling operations have become increasingly expensive as the need to drill deeper, in harsher environments, and through more difficult materials has become a reality. In addition, testing and evaluation of completed and partially finished wellbores has become commonplace, such as to increase well production and return on investment. Consequently, in working with deeper and more complex wellbores, it becomes more likely that tools, tool strings, and/or other downhole equipment may become stuck within the wellbore.
A downhole impact or jarring tool may be utilized to dislodge stuck downhole equipment. The impact or jarring tool (hereafter collectively referred to as simply “impact tool”) may be included as part of a tool string and deployed downhole along with the downhole equipment, or the impact tool may be deployed downhole after equipment already downhole becomes stuck. Tension may be applied from a wellsite surface to the deployed tool string via a conveyance means to store elastic energy in the tool string and the conveyance means. After sufficient tension is applied to the impact tool, the impact tool may be triggered to release the elastic energy in the impact tool and the conveyance means, thereby delivering an impact intended to dislodge the stuck downhole tool or to break a shear pin to disconnect a portion of the tool string from the stuck downhole tool.
However, in some downhole applications, such as in deviated wellbores or when multiple bends are present along the wellbore, friction between a sidewall of the wellbore and the conveyance means may reduce or prevent adequate tension from being applied to the impact tool. In such situations, the impact tool may be unable to produce an impact that is sufficient to dislodge the stuck downhole tool or break the shear pin.